Thermoplastic synthetic filamentary yarns are often designed for texturizing or other further processing to afford certain characteristics thereto. In a texturing operation, the filaments are subjected to heat, while being twisted by a false twist spindle, a friction disc or some other device, or while bent or distorted from linear form, to reorient the molecular structure of the filaments. A memory of a particular characteristic is retained, dependent upon the type processing steps utilized. Thereafter, additional heat is optional to further set or modify the reoriented structure. Stretch yarns and several kinds of set bulked yarns are produced commercially in this general fashion.
Under normal circumstances, the filamentary yarns are textured as bundles of filaments where the individual filaments unless properly pretreated, may abrade against adjacent filaments and/or portions of the processing equipment to the ultimate detriment of the yarn. Filaments having a particular finish thereon should thus preferably possess suitable frictional characteristics to avoid damage to the yarn while being texturized. Likewise, other very desirable finish characteristics are needed to achieve a good texturizing operation. Finish compositions have heretofore been developed toward this end.
Various and sundry finishes have heretofore been developed for application onto synthetic filaments at or subsequent to extrusion of the filaments. The particular finishes being applied have generally been accepted in their times as suitable for affording good lubrication and static qualities to the filament yarns to ensure proper processing during texturing, without allowing excessive damage to the yarn and/or causing excessive buildup of finish on the processing equipment. Prior art texturing finishes, also referred to as spin finishes, have been successful to a degree in protecting the filament yarn and affording stable operability.
As the art has progressed, however, equipment speeds and production rates have drastically increased due to larger demands for the yarn and, in part, due to the large capital investment required for additional equipment. Such increases in processing speeds have resulted in a need for higher yarn treatment temperatures at shorter exposure times. Other conditions have likewise changed such that in many cases, thermal and/or physical deterioration of the yarn finishes has resulted. Prior art finishes have generally volatilized to some considerable extent at the high processing temperatures. As the finish volatilizes, it is said to "fume", or produce a noticeable smoke, vapor or the like. Yarn characteristics afforded by the finish such as lubricity, antistatic qualities, and the like are, of course, altered by vaporization of an appreciable portion of the finish from the yarn.
Fumes from textile finishes cause multifaceted problems. The atmosphere is polluted by the fumes and must be purged, using expensive air handling systems. Condensation of the fumes on equipment and building surfaces creates housekeeping problems and quite possibly interferes with operation of the equipment. Contact between the yarn with the spin finish thereon and processing equipment causes some of the finish to rub off onto the equipment, which in time causes a finish buildup on the heated surfaces of equipment. Poor thermal stability of the finish on the equipment will cause the finish to degrade and leave a char residue on the equipment. A high fuming finish and one which pyrolyzes on the equipment to produce the char deposits leads to less than desirable yarn characteristics, e.g., broken filaments and processing conditions.
Attempts to overcome the above noted disadvantages have encountered further difficulty. Such attempts have generally not resulted in finishes that possess both a low degree of fuming and good thermal stability. At the same time, certain chemical compositions attack polyurethane aprons used on the texturing equipment causing the aprons to swell beyond the point of suitability for use. This feature must therefore be considered along with the low fuming and thermal stability characteristics. The present invention provides a textile finish that overcomes all the problems mentioned above. A low fuming propensity is realized along with good thermal stability against degradation. Good friction and static properties are imparted to the filaments which remain throughout processing. No significant effects have been noticed when the present finish is brought into contact with polyurethane machine components. All of these features point to significant improvement in the art.
The known prior art does not teach or suggest the present finish for synthetic filament yarn. Exemplary of the known prior art are U.S. Pat. Nos. 3,170,876 to Olney; 3,341,343 to Beiswanger et al; 3,341,451 to Dziuba et al; 3,470,095 to Pontelandolfo; 3,493,425 to Campbell; 3,503,880 to McMicken; 3,505,220 to Blake et al; 3,519,562 to Lanner; 3,522,175 to Katsumi et al; 3,541,138 to Emmons et al; 3,544,462 to Finch et al; 3,560,382 to Finch; 3,563,892 to Cooley; 3,644,143 to Flett; 3,652,419 to Karg; 3,681,244 to Obetz et al; 3,682,694 to Kato et al; 3,687,721 to Dardoufas; and 3,703,588 to Saito et al.